'V' block universal tube vise jaws
grabcad
Print two of these (I printed them with PLA and 100% infill), and they can be used for holding tubes in vices. They're useful for bicycle frame building and servicing things such as dropper posts. I'm not sure exactly what's the minimum and maximum tube diameter that these tube vice jaws can hold, but they should work for most bike frame tube sizes.Here's a link to the CAD in Onshape: https://cad.onshape.com/documents/235e7f3a2ca207eabc909dfb/w/a5dbb67fd00d225f0c78c1ff/e/36239f3fb65d77f07da5ccf8Be warned that I haven't used these much. Let me know if you print them and if they end up working for you. :)
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